eDNA Detection Decision Points

The flowchart above is an example of the steps involved in eDNA detection and the decisions involved during the analysis. 

1. The first step is to start the eDNA sampling.

2. Find the number of samples with target detection. If the number of samples with target detection is greater than one, move to the next step of collecting more samples to show evidence of reproducibility. If no samples have target detection, return to routine monitoring and ultimately back to starting eDNA sampling.

3. Once you collect more samples, begin or increase non-molecular sampling to confirm the eDNA detections. Once you’ve collected more samples, find the number of samples with target detection. If no samples have target detection, return to routine monitoring and ultimately back to starting eDNA sampling. If your number of samples with target detection is greater than one, decide upon the risk tolerance of the jurisdictional agency and applicable stakeholders.

4. Next, decision-makers should consider their risk tolerance. Risk tolerance is how much of an environmental, biodiversity, or financial loss a manager is prepared to handle relative to management objectives or priorities. If the value of the resources you are trying to protect is considered “low tolerance” (only willing to tolerate minimal loss if eDNA detections are indicative of an eventual infestation), you can continue to the decision point. If the value of the resources you are trying to protect is considered “high tolerance”, then you move to step 5.

5. Increase eDNA sampling and see if the number of detections is increasing or decreasing. If the detections are stable or increasing, you have reached your decision point. If the detections are decreasing, move to the next step.

6. Continue eDNA monitoring and see whether the detections are increasing or decreasing. After continued monitoring, if you find that the detections are increasing or are stable, you have reached the decision point. If the detections are decreasing, return to routine monitoring and ultimately back to starting eDNA sampling.